I was looking for a king sized mattress and ended up looking at many places, Sleep Country included. I ended up purchasing a king sized bed. The bed is good and delivery was on time.
The only problem I had was with the sales person. He talked down to both me and my brother, who was helping me decide on a mattress. He at several points started saying that we should just leave if we wanted it for less than the ticket price. After coming in with a competitive offer, he quickly decided that maybe he could cut some money off the price... but "only if I bought today." I felt like I was buying a used car.
They did after negotiation offer me the best value, so they are good, if you can put up with the attitude. If you don't want to deal with that, going to a department store might be a better option.